You should read their biographies, both by Walter Isaacson, I don't know how you can read those books and not see that they are more than just marketers. Isaac

You should read their biographies, both by Walter Isaacson, I don't know how you can read those books and not see that they are more than just marketers. Isaacson also wrote the definitive biographies for Einstein and Benjamin Franklin, among many other historical figures. Also "Masters of Doom" describes Carmack's career and idk about the word genius, but he is undeniably one of those engineers who's just 10x better than the average engineer.